A careful reading of the Twitter prospectus shows that insiders have been making moves to minimize investment and estate taxes before the IPO.

Twitter's elite aren't just planning the firm's initial public offering. They are protecting their estates.

The social-networking company's chairman, Jack Dorsey, is 36 years old, while Evan Williams, the largest individual shareholder, is 41, and Chief Executive Richard Costolo is 49. All three men have been making canny estate-planning moves, according to information from the IPO documents.